TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2399 SUBJECT: IPN triangulation of GRB030921 (large error box) DATE: 03/09/24 23:37:08 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, Konus, and Mars Odyssey GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS/Odyssey GRB team, and E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, report: Ulysses, Mars Odyssey-HEND, and Konus-Wind observed this GRB at 31103 seconds (GCN 2393). As observed by Ulysses, it had a duration of approximately 16 seconds, a 25-100 keV fluence of approximately 3E-06 erg/cm2, and a peak flux of approximately 5E-07 erg/cm2 s over 1.00 second. We have triangulated it to a preliminary, 3 sigma error box whose approximate area is 27000 sq. arcmin. and whose coordinates are: RA(2000) DEC(2000) ERROR BOX CENTER: 22 h 26 m 55.72 s 5 o 44 ' 14.82 " ERROR BOX CORNER 1: 22 h 27 m 53.21 s 5 o 53 ' 12.52 " ERROR BOX CORNER 2: 22 h 04 m 09.16 s 3 o 10 ' 28.20 " ERROR BOX CORNER 3: 22 h 47 m 58.35 s 6 o 52 ' 53.32 " ERROR BOX CORNER 4: 22 h 25 m 58.32 s 5 o 35 ' 07.34 " The Konus-Helicon annulus given in GCN 2393 intersects this error box and reduces its area to ~1100 sq. arcmin. The combined error box has coordinates: ERROR BOX CENTER: 22 h 27 m 14.28 s 5 o 44 ' 20.71 " ERROR BOX CORNER 1: 22 h 31 m 31.81 s 6 o 01 ' 30.80 " ERROR BOX CORNER 2: 22 h 22 m 56.53 s 5 o 27 ' 16.99 " ERROR BOX CORNER 3: 22 h 31 m 22.34 s 6 o 07 ' 47.14 " ERROR BOX CORNER 4: 22 h 23 m 06.43 s 5 o 20 ' 47.90 " This error box may be improved slightly.